Methods and devices for intra-atrial shunts having selectable flow rates

ABSTRACT

Devices and methods for treating heart disease by normalizing elevated blood pressure in the left and right atria of a heart of a mammal are disclosed. The devices are adapted to permit fluid flow across the membrane in which the device is implanted at first rate, and at a second rate, wherein a difference between the first rate and the second rate is not solely dependent upon variations in blood pressure differential across the membrane due to the heart&#39;s pumping cycle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional of U.S. Provisional ApplicationNo. 61/579,426, filed Dec. 22, 2011, entitled “Systems, Methods andDevices for Resizing Intra-Atrial Shunts” and of U.S. ProvisionalApplication No. 61/659,520, filed Jun. 14, 2012, entitled “AdjustableIntra-Atrial Shunts”, both of which are incorporated by reference hereinin their entireties.

FIELD OF THE INVENTION

The present invention relates to methods and devices for treating heartfailure. In particular, the present invention relates to methods anddevices for treating heart failure by reducing elevated blood pressurein a heart chamber by creating a pressure relief shunt. Additionally,the present invention relates to methods and devices for customizing,adjusting or manipulating the flow of blood through the shunt in orderto enhance the therapeutic effect of the pressure relief shunt.

BACKGROUND

Heart failure is a condition effecting millions of people worldwide.Heart failure includes failure of either the left side of the heart, theright side of the heart, or both. Left heart failure can lead toelevated pulmonary venous pressure, which may cause respiratoryproblems, including shortness of breath and exercise intolerance. Leftheart failure may be ascribed to a number of causes, including valvedisease, systolic failure of the left ventricle, and diastolic failureof the left ventricle. The adverse clinical result of each of theseconditions is similar; the heart failure leads to elevated pressure inthe left atrium and elevated pressure in the pulmonary veins, impedingproper flow of oxygenated blood through the blood supply. Therefore,there exists a need to treat the symptoms of left heart failure on thebody.

Heart failure has been further classified as either systolic heartfailure or diastolic heart failure. Diastolic heart failure refers toheart failure that is present without the presence of major valvedisease even while the systolic function of the left ventricle ispreserved. More generally, diastolic heart failure is failure of theventricle to adequately relax and expand in order to fill with blood,causing a decrease in the stroke volume of the heart. Presently, thereexist very few treatment options for patients suffering from diastolicheart failure. Therefore there exists a need for methods and devices fortreating symptoms of diastolic heart failure.

Some types of pressure relief shunts have been used to treat thesymptoms of diastolic heart failure. Examples of such types aredisclosed in U.S. Pat. No. 8,043,360 and U.S. Published PatentApplication No. 2011/0295366 A1. The long term effects of the creationof a pressure relief shunt can vary greatly depending on the amount ofblood flow through the shunt. These effects can include the gradualdevelopment of hypertrophic pulmonary arteries for cases withsignificant left to right shunting. The hypertrophy of the pulmonaryarteries in turn leads to worsening symptoms of heart failure. At theother end of the spectrum, the long term effect of the creation of apressure relief shunt may include a gradual decrease in the amount ofblood passing through the shunt such that the benefit of the proceduremay be reduced or eliminated.

The hemodynamic conditions associated with diastolic heart failure arenot static, and attempting to treat the disease with a static pressurerelief shunt represents a deficiency in the prior art. For example, if ashunt is sized too large the short term effect of the creation of apressure relief shunt may include a sudden worsening of heart failure.This phenomenon has been reported in similar procedures for heartfailure patients and may be considered a type of rebound stress.Furthermore, if the pressure relief shunt is sized too small the patientmay not experience any clinical improvement from the procedure. The sizeof the pressure relief shunt required for efficacious treatment ofdiastolic heart failure may be difficult to predetermine, and varieswith the condition of the patient and with the state of the underlyingdisease. With these deficiencies in mind, there still exists a need,among other needs, for an adaptive means of treating diastolic heartfailure by creating a clinically effective and safe pressure reliefshunt.

Along those lines, deployment techniques exist for creating a pressurerelief shunt in the atrial septum and then gradually allowing the shuntto open by slowly deflating a balloon which initially occludes theshunt. For example, the balloon may be gradually deflated over a periodof hours our days. This treatment method and apparatus suffers fromdeficiencies. For example, the requirement to leave a balloon in placein order to gradually open the pressure relief shunt can createsignificant problems such as the problem of keeping the balloon in placedespite the significant pressure differential across the shunt.Furthermore, the requirement to leave a catheter dwelling within thecirculation carries significant potential risks, including increasedrisk of pulmonary embolism, sepsis, sensitization or allergic reaction,and other potentially adverse clinical reactions.

The constantly evolving nature of heart failure represents a significantchallenge for the treatment methods currently disclosed in the priorart. Therefore, there is still a need for novel and adaptable methodsand devices for treating diastolic heart failure by creating a pressurerelief shunt which can be retrieved, repositioned, adjusted, expanded,contracted, occluded, sealed or otherwise altered as required to treatthe patient. Furthermore, there exists a need for devices and methodsfor treating diastolic heart failure which can automatically self-adjustover time either in accordance with the gradual hemodynamic changesassociated with heart failure or in anticipation of these changes.

SUMMARY OF THE INVENTION

In general, the present invention concerns treating heart disease byreducing both left atrial and pulmonary venous pressure. To this end,devices and methods are disclosed herein which may include the creationof a pressure relief shunt in the atrial septum or the placing of adevice having a changeable hydraulic diameter into an already existingaperture in the atrial septum. Furthermore, devices and methods aredisclosed herein which allow for adjusting the pressure relief shunt inresponse to the natural progression of the patient during the course oftreatment. Additionally, devices and methods are disclosed which providea treatment which may be adjusted to or which automatically adjusts tothe changing conditions in the body as a result of the creation of thepressure relief shunt or the presence of the extant atrial septalaperture. Furthermore, devices and methods are disclosed herein whichmitigate the risk of acute worsening of heart failure following thecreation of a pressure relief shunt or of an extant atrial septalaperture by allowing for gradual increase in the hydraulic diameter ofan implanted device after implantation. Devices and methods aredisclosed herein which significantly mitigate the risk of laterdevelopment of pulmonary hypertrophy by implanting a device whichgradually decreases hydraulic diameter in size over time or in responseto the natural hemodynamic changes in the heart.

In some embodiments of the present invention, an implantable shuntingdevice is provided. The inventive device includes a pair of anchors,each comprising a plurality of segments, that are adapted to hold thedevice in place within a membrane wall, e.g. the atrial septum, and ashunting section adapted to permit fluid flow across the membrane wallfirst at first rate and then at a second rate at a later selectabletime.

In some embodiments, the implantable shunting device is adapted to bemanually adjusted to change the rate of fluid flow therethrough. Forexample, the inventive device may include an element which causes thehydraulic diameter of the shunting section to be manually alterable.Such elements may include a coil which may be incrementally wound,stretched, and/or compressed to selectively alter its hydraulicdiameter. Such elements may include a tube that can be plasticallydeformed to alter its hydraulic diameter.

In some embodiments, the implantable shunting device is adapted toautomatically change the rate of fluid flow therethrough. For example,the inventive device may have a first configuration which allows apredetermined flow rate to communicate from a high pressure region to alow pressure region across a membrane wall and be adapted to transformover a predetermined period of time into one or more otherconfigurations in order to allow a different flow rate or different flowrates to communicate from the high pressure region to the low pressureregion. The transformations may be gradual or may occur in discretesteps or may be a combination of gradual change with abrupt changes. Theflow rate changes may be positive or negative or may alternate betweenthe two.

In some embodiments, the implantable shunting device is to permit manualadjustment of the fluid flow rate through the device. For example, insome embodiments, the inventive device includes a hollow tubular bodyand a number of septal anchoring members, which anchor the inventivedevice to the atrial septum. The tubular body may be configured with anoriginally-deployed diameter (a first diameter) which may be expected toprovide an efficacious treatment for an average patient. Alternatively,the first diameter of the tubular body may initially be undersized suchthat an effective treatment may be achieved in some subset of patientswhile the risk of acute worsening of heart failure following theimplantation of the shunt is substantially decreased among all patients.The inventive device is further configured to be manually expanded orcontracted by an adjustment device to second, third, fourth, . . . ,etc. diameters (also referred to herein as “subsequent diameters”). Theinventive device may include interlocking features which maintain theinternal diameter that is set by the adjustment device. Alternatively,the tubular body of the inventive device may be made from an elasticallydeformable, heat setting, pressure-sensitive, or otherwise malleablematerial such that the diameter of the device remains stable after beingset by the adjustment device.

In some embodiments, the inventive device includes an elongate tubularbody, an internal member having an orifice, and a number of anchoringmembers for anchoring the tubular body to the atrial septum. The tubularbody further includes an internal fastening feature which releasablyclasps the internal orifice-containing shunt member. The internalorifice-containing member has an internal diameter which is configuredto allow a therapeutic amount of blood to flow through the shunt. Theinternal member may be released from the fastening feature of thetubular body with a special retrieval tool and may then be repositionedor replaced with another internal shunt member. The replacement internalshunt member may feature a substantially larger or substantially smallerinternal diameter, thus causing the device to have a differentsubsequent diameter than the first diameter. This replacement of theinternal member may therefore be used to adjust the amount of blood flowthrough the shunt in order to respond to hemodynamic changes in theheart.

In some embodiments, the inventive device including a tubular body and anumber of anchoring members is disclosed, where the tubular body may beconfigured such that its first diameter initially allows only a smallvolume of blood to shunt from the left atrium to the right atrium. Thetubular body may then be designed to gradually expand over the course ofdays, weeks, or months, to subsequent diameters that allow a largervolume of blood to pass through the shunt. The shunt may be configuredso that the internal portion or orifice will expand to a predeterminedfinal subsequent diameter in order to allow a therapeutic amount ofblood flow through the shunt. In such embodiments, the orifice of theinventive device may be configured to expand slowly so that the risk ofacute worsening of heart failure that may be caused by a suddenhemodynamic change is substantially reduced.

In some embodiments, the inventive device includes a tubular body and anumber of anchoring members and is configured to open to an internaldiameter that allows sufficient blood to flow through the shunt in orderto reduce the left atrial and pulmonary venous pressure. The tubularbody may be configured such that over time the internal diameter of theshunt gradually contracts. The internal diameter of the inventive devicemay be designed to shrink to a predetermined final diameter. Thepredetermined final diameter may be sized to allow some clinicallyrelevant blood flow through the shunt while simultaneously eliminatingthe risk of developing hypertrophic pulmonary arteries. Alternatively,the inventive device may be configured such that given enough time theinternal diameter becomes completely occluded and blood flow through theshunt is prevented.

In some embodiments, the inventive device featuring a tubular body and anumber of anchoring members may be configured to, at first, graduallyopen the first internal diameter of the shunt and then much latergradually close the subsequent internal diameter of the shunt. Thegradual shrinking or expanding of the inventive device is used tocontrol the amount of blood through the shunt in anticipation of thehemodynamic changes that occur over time due to the progression of heartfailure and due to the creation of a pressure relief shunt. In stillother embodiments the gradual opening or closing of the inventive devicemay include prolonged periods of static blood flow. For example, theinventive device may be implanted with a small diameter, then over timeexpand to a second larger diameter and remain there for some period oftime. The delay may allow for additional testing or observation byhealth care personal. After the static delay period the inventive devicemay be allowed to further expand to a still larger third diameter.

In some embodiments of the present invention, the inventive deviceincluding a tubular body and a number of anchoring members may beimplanted into an atrial septum. The tubular body of the inventivedevice includes an anchoring or clasping feature which can be used by aphysician to close the inventive device if desired.

In some embodiment, an adjustable intra-atrial shunt includes a retainerhaving a plurality of struts and a plurality of apices joining thestruts to form a generally cylindrical body having a left retainingflange and a right retaining flange, the tubular body adapted to fitwithin a wall of an atrial septum, the left retaining flange adapted tofit within a left atrium of a heart and the right retaining flangeadapted to fit within a right atrium of a heart. The adjustableintra-atrial shunt also includes a removable and/orremovable/replaceable insert for placement within the retainer, theinsert comprising a generally tubular body having a longitudinal openingto allow a flow of blood from an area of high pressure of the heart toan area of low pressure of the heart and a retrieval loop for removal ofthe insert from the retainer and the atrial septum, wherein theremovable/replaceable insert and the opening allow a first rate of bloodflow from an area of high pressure of the heart to an area of lowpressure of the heart, and wherein the adjustable intra-atrial shunt isadapted to allow a second rate of blood flow from an area of highpressure of the heart to an area of low pressure of the heart byreplacing the removable/replaceable insert with a secondremovable/replaceable insert having an opening of a different size.

In some embodiments, an adjustable, intra-atrial shunt includes aretainer having a plurality of struts and a plurality of apices joiningthe struts to form a generally cylindrical body having a left retainingflange and a right retaining flange, the tubular body adapted to fitwithin a wall of an atrial septum, the left retaining flange adapted tofit within a left atrium of a heart and the right retaining flangeadapted to fit within a right atrium of a heart of a patient. Thisembodiment also includes a removable/replaceable insert for placementwithin the retainer, the insert comprising a plurality of flaps mountedon a generally cylindrical body having at least one opening to allow aflow of blood from an area of high pressure of the heart to an area oflow pressure of the heart, wherein the removable/replaceable insert andthe at least one opening allow a first rate of blood flow from an areaof high pressure of the heart to an area of low pressure of the heartwhen first implanted into a patient, and wherein theremovable/replaceable insert is adapted to allow a second rate of bloodflow from an area of high pressure of the heart to an area of lowpressure of the heart after portions of the insert absorb into thepatient.

In some embodiments, an adjustable, intra-atrial shunt includes aretainer having a plurality of struts and a plurality of apices joiningthe struts to form a generally cylindrical body having a left retainingflange and a right retaining flange, the tubular body adapted to fitwithin a wall of an atrial septum, the left retaining flange adapted tofit within a left atrium of a heart and the right retaining flangeadapted to fit within a right atrium of a heart of a patient. Thisembodiment also includes a removable/replaceable insert for placementwith the retainer, the insert comprising at least one flap mounted on abody having at least one opening to allow a flow of blood from an areaof high pressure of the heart to an area of low pressure of the heart,wherein the insert and the at least one opening allow a first rate ofblood flow from an area of high pressure of the heart to an area of lowpressure of the heart when first implanted into a patient, and whereinthe insert is adapted to allow a second rate of blood flow from an areaof high pressure of the heart to an area of low pressure of the heartafter at least one portion of the insert absorbs into the patient.

In some embodiments, methods for treating diastolic heart failure aredisclosed. The methods include implanting an inventive device into theatrial septum in order to decrease the left atrial and pulmonary venouspressure. The methods further include measuring the patient'shemodynamic status and heart failure indicators. Finally, the methodincludes adjusting the amount of blood flow through the inventive devicein order to more effectively treat the heart disease. In someembodiments the methods for treating heart failure may include closingthe inventive device, expanding the inventive device, collapsing theinventive device, or exchanging either the entire shunt or somecomponents of the inventive device in order to increase the efficacy ofthe procedure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully apparent from the followingdescription and appended claims, taken in conjunction with theaccompanying drawings. Understanding that these drawing merely depictexemplary embodiments, they are, therefore, not to be consideredlimiting. It will be readily appreciated that the components of thepresent invention, as generally described and illustrated in thedrawings herein, could be arranged and designed in a wide variety ofdifferent configurations. It is to be kept in mind that each of thedrawings presented herein is a schematic drawing that may only depictsome of the features of the subject matter it is being used to describe.

FIG. 1 is a partially cross-sectional view of a patient's heart in whicha catheter is extending through the atrial septum.

FIG. 2 is a partially cross-sectional view of a patient's heart in whichan embodiment of an implantable device has been implanted within anaperture in the atrial septum.

FIG. 3 is a partially cross-sectional view of a patient's heart as inFIG. 2 in which a catheter with a retrieval device is poised to engagethe conical tail of the implantable device.

FIG. 4 is cross-sectional view of an embodiment of an implantable devicewhich has been implanted within an aperture in the atrial septum.

FIG. 5 is a partially cross-sectional view of a patient's heart as inFIG. 4 in which a catheter having a balloon extends through theimplantable device.

FIG. 6 is partially cross-sectional view of an embodiment of animplantable device which has been implanted within an aperture in theatrial septum.

FIG. 7 is partially cross-sectional view of an embodiment of animplantable device which has been implanted within an aperture in theatrial septum.

FIG. 8A is a partially cross-section view of an embodiment of animplantable device which is similar to that shown in FIG. 7, except forthe alteration to its diamond shaped struts.

FIG. 8B is a partially cross-section view of an embodiment of animplantable device which is similar to that shown in FIG. 8A, except forthe alteration to its axially stiff members.

FIG. 9 is an end view of an embodiment of an implantable device.

FIG. 10A is an exploded side view of an embodiment of an implantabledevice.

FIG. 10B is partially cross-sectional view of the embodiment of FIG. 10Awhich has been implanted within an aperture in the atrial septum showingthe implantable device just after implantation. Only a small portion ofthe frame of the device is shown in this drawing.

FIG. 10C is a partially cross-sectional view as in FIG. 10A but showingthe implantable device at a later time after the absorption of thebiosorbable material which at one end of the device. Only a smallportion of the frame of the device is shown in this drawing.

FIG. 10D is a partially cross-sectional view as in FIG. 10C but showingthe implantable device at a still later time after the absorption of thebiosorbable material at the other end of the device. Only a smallportion of the frame of the device is shown in this drawing.

FIG. 11 is a flow diagram of a method embodiment.

FIG. 12 is a cross-sectional view of an embodiment of an implantabledevice after implantation in an aperture of an atrial septum.

FIG. 13 is a partially exploded view of the inventive device of FIG. 1

FIG. 14 is a partially exploded view of another embodiment of animplantable device.

FIG. 15 is a cross-sectional view of the insert portion of an embodimentof an implantable device.

FIG. 16 is a perspective view of an insert portion of an embodiment ofan implantable device.

FIG. 17 is a perspective view of an insert portion of an embodiment ofan implantable device.

FIG. 18 is an end view of an insert portion of an embodiment of animplantable device.

FIG. 19A is a perspective view of an insert portion of an embodiment ofan implantable device.

FIG. 19B is a cross-sectional view taken along line 19B-19B of theinsert portion of FIG. 19A.

FIG. 20 is a partial perspective view of an end of an insert portion ofan implantable device.

FIG. 21 is a partial perspective view of an end of an insert portion ofan implantable device.

DESCRIPTION OF PREFERRED EMBODIMENTS

Certain specific details are set forth in the following description andFIGS. to provide an understanding of various embodiments. Those ofordinary skill in the relevant art will understand that they canpractice other embodiments without one or more of the details describedbelow. Further, while various processes are described herein withreference to steps and sequences, the steps and sequences of steps arenot be understood as being required to practice all embodiments of thepresent invention.

Unless otherwise defined, explicitly or implicitly by usage herein, alltechnical and scientific terms used herein have the same meaning asthose which are commonly understood by one of ordinary skill in the artto which this present invention pertains. Methods and materials similaror equivalent to those described herein may be used in the practice ortesting of the present invention. In case of conflict between a commonmeaning and a definition presented in this document, latter definitionwill control. The materials, methods, and examples presented herein areillustrative only and not intended to be limiting.

Certain specific details are set forth in the following description andFIGS. to provide an understanding of various embodiments. Those ofordinary skill in the relevant art will understand that they canpractice other embodiments without one or more of the details describedbelow. Further, while various processes are described herein withreference to steps and sequences, the steps and sequences of steps arenot be understood as being required to practice all embodiments of thepresent invention.

Unless expressly stated otherwise, the term “embodiment” as used hereinrefers to an embodiment of the present invention.

Unless a different point of reference is clear from the context in whichthey are used, the point of reference for the terms “proximal” and“distal” is to be understood as being the position of a practitioner whowould be implanting, is implanting, or had implanted a device into apatient's atrial septum from the right atrium side of a patient's heart.An example of a context when a different point of reference is impliedis when the description involves radial distances away from thelongitudinal axis or center of a device, in which case the point ofreference is the longitudinal axis or center so that “proximal” refersto locations which are nearer to the longitudinal axis or center and“distal” to locations which are more distant from the longitudinal axisor center.

As used herein, the terms “subject” and “patient” refer to any animal,such as a mammal like livestock, pets, or humans. Specific examples of“subjects” and “patients” include, but are not limited, to individualsrequiring medical assistance, and in particular, requiring treatment forsymptoms of heart failure.

As used herein, the term “pressure differential” means the difference inpressure between two points or selected spaces; for example between oneside of a flow control element and another side of the flow controlelement.

As used herein, the term “embolic particle” means any solid, semi-solid,or undissolved material, that can be carried by the blood and causedisruption to blood flow when impacted in small blood vessels.,including thrombi.

As used herein, the terms “radially outward” and “radially away” meansany direction which is not parallel with the central axis. For example,considering a cylinder, a radial outward member could be a piece of wireor a loop of wire that is attached or otherwise operatively coupled tothe cylinder that is oriented at some angle greater than 0 relative tothe center longitudinal axis of the cylinder.

As used herein, the term “axial thickness” means the thickness along anaxis parallel to the center longitudinal axis of a shape or component.

As used herein, the term “axial direction” means direction parallel tothe center longitudinal axis of a shape or component.

As used herein, a “sealable connection” is an area where componentsand/or objects meet wherein the connection defines provides for aninsubstantial leakage of fluid or blood through the subject area.

As used herein, the term “lumen” means a canal, duct, generally tubularspace or cavity in the body of a subject, including veins, arteries,blood vessels, capillaries, intestines, and the like.

As used herein, the term “sealably secured” or “sealably connected”means stably interfaced in a manner that is substantially resistant tomovement and provides resistance to the flow of fluid through or aroundthe interface.

As used herein the terms “bio-resorbable” and “bio-absorbable” refer tothe property of a material that allows it to be dissolved or absorbed ina living body.

As used herein, the term “hydraulic diameter” means the overall flowrate capacity of a conduit taking into consideration the number andconfiguration of the inlets and outlets of the conduit.

As used herein, the terms “gradual” and “gradually” mean that somethingoccurs over the course of time, either in a stepwise fashion or acontinuous fashion. For example, the hydraulic diameter of an inventivedevice may gradually change in a step-wise fashion from an initial valueto a later different value when an absorbable suture that initiallyrestrains a geometrical change in the device breaks during itsabsorption and is no longer able to restrain the geometrical change. Asanother example, the hydraulic diameter of an inventive device maygradually change in a continuous fashion when an absorbable diaphragmhaving an initial orifice is continuously absorbed over time so that thediameter of the orifice continuously increases in diameter.

As used herein, the term “whole multiple” means the product contains nodecimal.

It is to be understood that whenever relational numbers are used herein,e.g., “first,” “second,” etc., they are used for convenience ofdescription and so they are to be interpreted with regard to theparticular embodiment or claim in which they are presented, rather thanas applying globally throughout this document to all embodiments or allclaims. Thus, for example, in one embodiment it may be more convenientto use the term “first flange” to describe a flange that would belocated in the right atrium when the device of that embodiment isimplanted in an atrial septum, whereas it might be more convenient touse the term “first flange” in another embodiment to refer to refer to aflange that would be located in the left atrium when the implantabledevice of that embodiment is implanted.

It is to be understood that all flow rates are compared at identical thepressure differentials and fluid characteristics. Thus, whenever adevice or a portion of a device is said to be adjustable from a firstflow rate to a second flow rate, it is to be understood that thehemodynamic conditions under which those flow rates occur are identicalto one another.

It should be appreciated that embodiments are applicable for use inother parts of the anatomy or for other indications. For instance, adevice such as that described in this disclosure could be placed betweenthe coronary sinus and the left atrium for the same indication. Also, apressure vent such as is described in this disclosure could be placedbetween the azygous vein and the pulmonary vein for the same indication.

It is also to be appreciated that although liners or internal sheaths toassist in directly fluid flow through the inventive device are describedbelow with regard to only some of the embodiments, the other describedembodiments may be adapted to include the use of liners or internalsheaths.

The present invention may include a percutaneously deliverable device.In some embodiments, the device has a straightened, elongated,low-profile delivery configuration suitable for delivery via a deliverysystem. The device may have a generally radially expanded and sometimesshortened deployed profile. For example, it can have a distal anchoringportion positioned on the left atrial side of the septum, a rightanchoring portion positioned on the right atrial side of the septum,and/or a shunt portion, sometimes referred to as a “core segment”,positioned through an aperture in the septum. The anchoring portions aresometimes referred to herein as “flanges”. A flange may be annularflanges. An annular flange may comprise a plurality of segments. It isto be understood that in some embodiments having right and left anchorsthat the anchors may be connected and in some embodiments they areintegrally connected.

In some embodiments, when a device according to the present invention isdeployed across a patient's atrial septum, the distal and proximalflanges are located left and right to the septum respectively. The coresegment of the device creates a shunt or passageway allowing blood flowacross the aperture. Generally, the left atrium has a higher pressurethan the right atrium and the blood tends to flow from the left atriumacross the shunt to the right atrium. The greater the cross-sectionalsize of the core segment at any point in time, i.e., its shunting size,the greater amount of blood flows from the left to right atria. Thegreater the amount of blood flows to the right atrium, the greater theleft heart decompresses. The left atrial pressure can be measureddirectly with a catheter in the left atrium or indirectly by measuringthe pulmonary capillary wedge pressure (PCWP) during a right heartcatheterization. The normal values of the mean left atrial pressure aretypically in the range of 6-12 mmHg. The shunting size of the coresegment of devices of the present invention may be tailored so that,during and post implantation, the left atrial pressure would reach thenormal range of 6-12 mmHg. Thus for a DHF patient having a significantlyelevated left atrial pressure, a device with a bigger shunting sizeshould be used to restore the left atrial pressure to the normal range.For a DHF patient with a moderately elevated left atrial pressure, adevice with a smaller shunting size should be used to restore the leftatrial pressure.

The left atrial v-wave is the left atrial pressure at the end of anatrial diastole but immediately before the opening of the mitral valve.The left atrial v-wave represents the peak of the left atrial pressure.The size of the left atrial v-wave is determined partially by the amountof blood entering the left atrium. The normal range of left atrialv-wave is 6-21 mmHg. The shunting size of the core segment of thedevices of the present invention may be tailored so that the left atrialv-wave would reach the normal range of 6-21 mmHg. Thus, for a DHFpatient with significantly elevated left atrial v-waves, a device with abigger shunting size can be used to restore the v-wave to the normalrange. For a DHF patient with moderately elevated left atrial v-waves, adevice with a smaller shunting size should be used to restore the v-waveto the normal range.

Systematic oxygen saturation is routinely monitored during apercutaneous implantation procedure. With the decompression of the leftheart, the shunting size of the core segment of devices of the presentinvention may be tailored so that the systemic oxygen saturation levelduring and/or after an implantation procedure is maintained in the rangeof 75-100%. For a DHF patient with an elevated left atrial pressure, thehigher the left atrial pressure elevation is prior to a treatment, thegreater the shunting size should be used to maintain the systemic oxygensaturation level at a safe range; and the lower is the left atrialpressure elevation is prior to a treatment, the smaller the shuntingsize should be used to maintain the systemic oxygen saturation level atits safe range.

The ratio of pulmonary blood flow to systematic blood flow is defined asa Qp:Qs ratio. In a healthy heart, the Qp:Qs ratio is 1:1. In a DHFpatient, Qp:Qs ratio is generally greater than 1:1. Some go beyond2.5:1. The devices of the present invention be used to restore the Qp:Qsratio to or close to the normal range. Thus, the left-to-right flowproduced by the device may be tailored so that the Qp:Qs ratio would atsome time reach the acceptable range of 1:1 to 1.5:1.

The greater the left-to-right shunting flow which is generated by thedevice, the lesser amount of blood remains inside the left atrium and,later, enters the left ventricle. The smaller is the shunting flow, thegreater amount of blood remains inside the left atrium and, later,enters the left ventricle. The normal values of mean left ventriclepressure are typically in the range of 40-80 mmHg. Thus, the shuntingsize of the core segment of the device may be tailored so that the leftventricle pressure would reach the normal range of 40-80 mmHg. For a DHFpatient with a significantly elevated left ventricle pressure, a devicewith a bigger shunting size may be used to restore the left ventriclepressure to the normal range. For a DHF patient with a moderatelyelevated left ventricle pressure, a device with a smaller shunting sizemay be used to restore the left ventricle pressure to the normal range.

With the left-to-right shunting flow created by the device, the amountof blood inside the right atrium increases, which results in an elevatedright atrium pressure. The greater the left-to-right shunting flow is,the greater is the amount of the blood that remains inside the rightatrium, and in turn, the greater is the elevation in the right atrialpressure. The smaller the left-to-right shunting flow is, the lesser isthe amount of the blood that remains inside the right atrium, and inturn, the lesser is the elevation in the right atrial pressure. Thenormal values of the mean right atrial pressure are typically in therange of 4-12 mmHg. Thus, the shunting size of the core segment of thedevice may be tailored so that the right atrial pressure would remainthe range of 4-12 mmHg. Thus for a DHF patient with the right atrialpressure in the lower range, such as in the range of 4-6 mmHg, a devicewith a bigger shunting size can be used, and for a DHF patient with theright atrial pressure within the higher range, such as in the range of10-12 mmHg, a device with a smaller shunting size should be used toprevent right atrium overload.

With the left-to-right blood flow created by the device, the amount ofblood inside the right atrium increases, and the amount of bloodentering into the right ventricle increases, which results in anelevated right ventricle peak systolic pressure. The greater is theleft-to-right shunt, the greater is the amount of blood remains insidethe right atrium, and in turn the greater is the amount of blood entersinto the right ventricle, and the greater is the elevation in the rightventricle peak systolic pressure. The lesser the left-to-right shunt,the lesser is the amount of blood remains inside the right atrium, andin turn the lesser is the amount of blood enters the right ventricle,the lesser is the elevation in the right ventricle peak systolicpressure. The normal values of the mean right ventricle peak systolicpressure are typically in the range of 20-40 mmHg. Thus, the coresegment of the device may be tailored so that the right ventricle peaksystolic pressure would not exceed the normal range of 20-40 mmHg. Thusfor a DHF patient with the right ventricle peak systolic pressure withinthe lower range, such as in the range of 20-30 mmHg, a device with abigger shunting size could be used; and for a DHF patient with the rightventricle peak systolic pressure within the higher range, such as in therange of 30-40 mmHg, a device with a bigger shunting size should be usedin order to prevent right ventricle overload.

With the left-to-right blood flow created by the shunt device, theamount of blood remaining inside the right atrium increases, and inturn, the pressure difference between the right and left atriumdecreases. The greater is the left-to-right shunt, the greater is theamount of blood remains insider the right atrium and the greaterreduction in the pressure difference between the left and right atria.The smaller is the left-to-right shunting flow, the lesser amount ofblood remains inside the right atrium and the lesser reduction is in thepressure difference between the left and right atria. The normal valuesfor the pressure difference between the left and right atria aretypically in the range of 2-10 mmHg. Thus, the shunting size of the coresegment of the device may be tailored so that the pressure differencebetween the left and right atria would not exceed the range of 2-10mmHg. Thus for a DHF patient with a pressure difference between the leftand right within the lower range, such as in the range of 2-5 mmHg, adevice with a bigger shunting size can be used. For a DHF patient with apressure difference between the left and right atria within the higherrange, such as in the range of 5-10 mmHg, a device with a smallershunting size should be used in order to prevent right atrium overload.

FIG. 1 depicts a schematic view of a patient's heart and shows anexample of a delivery catheter. An implant delivery catheter sheath 101is shown extending from the inferior vena cava (IVC) 103, through theright atrium 105, across the atrial septum 107, and finally into theleft atrium 109. By convention the left atrium is depicted on the rightside of FIG. 1, and the right atrium is depicted on the left side ofFIG. 1. This convention will be used throughout this document. Inessence, the heart of FIG. 1 represents a simplified view of a patient'sheart. A conical dilating catheter 111 extends from the distal end ofthe delivery sheath while a crossing wire 113 further extends out of thedilating catheter. The implant delivery catheter is shown having crossedthe atrial septum at the region of the fossa ovalis 115, where theatrial septum is very thin.

The implant delivery catheter of FIG. 1 is configured to house aninventive device implant. The conical dilating catheter of FIG. 1 isconfigured to move axially within the implant delivery catheter, suchthat the conical surface may be initially used to dilate a small hole inthe atrial septum and then may later be advanced or retracted in orderto facilitate the deployment of the inventive device implant. Thetransition 117 between the dilator and the sheath is carefully designedsuch that a very minimal step exists between the two components.

The crossing wire of FIG. 1 may be any suitably stiff wire currentlyavailable for catheter procedures, or it may be custom made for theprocedure. The wire may include a sharpened tip in order to more easilyperforate the septum. The wire may be made of stainless steel, Nitinol,or any other suitable material. After crossing the septum the wire maybe withdrawn from the body, or may be left behind in order to facilitythe advancement of further devices and catheters into the body. Inaddition the wire may feature a curved distal section (as shown) inorder to prevent the user from accidentally puncturing the wall of theleft atrium. In embodiments of the present invention, the guide wire isa 0.9 mm (0.035″) J-curve Nitinol wire. In other embodiments of thepresent invention the guide wire may be similar to the wires used in thetreatment of total coronary occlusions. The design, manufacture, and useof guide wires for penetrating tissue are well known in the art.

The dilation catheter of FIG. 1 may be manufactured in a number of ways,and may be made of any suitable biocompatible material. A simpledilation catheter might be made from LDPE, HDPE, or FEP, and may featurea heat formed or over-molded conical tip. Another suitable dilationcatheter construction might include a PEBAX or nylon braided shaft witha specially designed conical cap. The dilation catheter features agenerally circular cross-section, however ridges or texturing may beemployed in order to more efficiently dilate the septum by creatinglocalized stress-concentration in the tissue near the ridges. Inaddition, the distal conical section of the dilator may incorporate anumber of cutting features, such as a small metallic blades, orsharpened plastic protrusions, in order to more effectively dilate theatrial septum. In some embodiments of the present invention, the OD ofthe dilator is roughly between 3 mm and 5 mm.

Still referring to FIG. 1, the dilation catheter extends from an accesspoint (not shown) in the lower veins, and extends into the right atriumthrough the inferior vena cava. In alternative embodiments of thepresent invention the dilation catheter may access the atrial septum byother means, including from the jugular vein (not shown) and through thesuperior vena cava 119. In addition, access to the atrial septum may beprovided by other means, including through minimally invasive surgery,and through other major vessels in the body.

Continuing to refer to FIG. 1, the delivery catheter may be configuredsuch that in order to deploy a inventive device implant (not shown) theuser may simply advance the catheter to the approximate position shownin the FIG. and then retract the sheath relative to the dilator, therebyexposing the implant to the tissue. The dilator and guide wire may thenbe withdrawn from the atrial septum, leaving behind the therapeuticimplant. Alternatively, the dilator may be withdrawn from the sheath andthe sheath may then be used as a conduit for advancing a simple deliverycatheter. The inventive device delivery catheter may be configured tocarefully expand the left atrial side of the shunt in the left atriumwith the sheath in place in the atrial septum. The sheath may then bewithdrawn and the delivery catheter may be further configured to allowthe right atrial side of the implant to expand in order to fully deploythe interatrial inventive device. The implant may be configured suchthat it is collapsed into a delivery configuration featuring a smalldelivery diameter and then naturally expands into the implantedconfiguration featuring a larger implanted diameter.

It is to be understood that the delivery catheter described with regardto FIG. 1 is only an example of a delivery catheter that can be usedwith the inventive devices. After extraction, the inventive device wouldbe drawn into the catheter for removal. The inventive devices may alsobe used with other delivery catheters known in the art. Examples ofdelivery catheters are disclosed in U.S. Published Patent ApplicationNo. 2011/0295366 A1.

Referring now to FIG. 2, an inter-atrial inventive device 201 isdepicted as implanted into the atrial septum 107. The inventive deviceincludes a tubular body 203 and a series of anchoring elements 205. Theanchoring elements are designed to extend from the tubular body andengage the tissue of the atrial septum near the fossa ovalis 115. Aconical tail 207 extends from one end of the shunt out into the rightatrium. The conical tail has a very open mesh-like structure such thatit does not impede blood flow through the shunt even though it connectsto the tubular body circumferentially. The tubular shunt is configuredto allow blood to flow through the internal diameter of the tubularbody, thereby acting as a means to limit the pressure differentialacross the atrial septum.

Still referring to FIG. 2, the tubular body of the inventive device maybe made of any suitable biocompatible implant material. The tubular bodymay include a stent-like skeleton, which may be collapsible tofacilitate delivery of the device. The tubular body may further includean internal or external sheath in order prevent blood from flowingaround the device instead of through the internal diameter of the shunt.The stent-like skeleton of the tubular body may be made of a laser-cutNitinol tube, or may instead be made of woven Nitinol wire. The stentmember may instead be made of stainless steel, MP35N, Cobalt-chromium,other shape-memory type alloys, other materials referred to assuper-elastic alloys, or a plastic or polymeric material. Methods ofmanufacture of stents and stent-like implants are well established inthe relevant prior art.

The conical tail of the interatrial shunt of FIG. 2 is configured suchthat it extends into the right atrium and therefore represents a featurewhich could be engaged by an appropriate retrieval catheter. Theretrieval of the interatrial shunt is depicted in FIG. 3.

Referring now to FIG. 3 a snaring catheter 301 is shown having beenpositioned near the conical tail 207 of the interatrial inventive device201. The catheter consists of a radio-opaque tip 303, a series ofbasket-wires 305, and a delivery sheath 307. The snare may be opened orclosed by respectively retracting or advancing the delivery sheath.Advancing the delivery sheath over the basket-wires causes them tocollapse into the sheath, while retracting the delivery sheath away fromthe basket-wires allows the wires to return to their open configuration.In this way a user is able to snare the conical tail of the inventivedevice by advancing the snaring catheter into the right atrium near theinventive device and retracting the delivery sheath exposing thebasket-wires. The basket-wires would then expand in a way that makesentanglement with the conical tail very likely. The user may thenre-advance the delivery sheath and capture the conical tail. The usermay then withdraw the catheter from the body, in turn pulling theinteratrial shunt out of the atrial septum. In this way the snaringcatheter represents a retrieval catheter and may be used to remove animplanted interatrial shunt. Once this step is completed the user maythen implant a new shunt of a larger or smaller internal diameter, ormay instead replace the shunt with an occluding device, or may otherwiseseal the hole in the septum. In this way the implant of FIG. 2 and theretrieval device of FIG. 3 represent a system for adjusting theinventive device in order to allow for the treatment of a progressing orotherwise changing disease state.

FIG. 4 depicts a sectioned view of an embodiment of the presentinvention featuring an adjustable inventive device 400 as implanted intoan interatrial septum 107. The inventive device of FIG. 4 includes anelongate tubular body 203 and a series of anchoring members 205. Theelongate tubular body is constructed in roughly concentric layers. Theinner most layer is an optional internal liner 401 which directs theblood flow through the device from the left atrium 109 into the rightatrium 105. The next layer is a stent like body 403 which ismanufactured of a plastically deformable material. This layer isrepresented in cross-section as a series of rectangular cross-hatchedregions. The plastically deformable stent like member is constructedfrom a material such as stainless steel, and is designed such that whenexpanded, contracted, or otherwise deformed to a desired diameter itwill naturally remain in the deformed state. The outer most layer of thetubular body of FIG. 4 is a super-elastic layer 405 from which theanchoring members extend. The super-elastic layer has a number of hookfeatures 407 which couple the elastic layer to the plasticallydeformable layer. The super-elastic layer may be manufactured bylaser-cutting a nitinol hypotube and then shape-setting the hooks andanchoring members into the desired shape. A series of knotted sutures409 are shown connecting the innermost layer, i.e., the internal liner401, and the plastically deformable layer, i.e., stent like body 403;however the individual layers may be connected by any suitable means inorder to form a cohesive tubular shunt body. It is to be understood thatalthough for the sake of clarity the internal liner 401 is shown asbeing attached only at its ends to the stent like body 403, the internalliner 401 may be attached at any and all points along its length toeither the stent like body or the super-elastic layer 405.

The layered construction of the tubular body of FIG. 4 allows for auser-adjustable shunt to be created. The user may adjust the size of theshunt by first engaging the shunt and then by deforming the plasticallydeformable layer as desired. The deformation is frozen in place by theplastically deformable layer. This deformation is then transferred tothe super-elastic layer and the internal layer because the layers areinterconnected and because the plastically deformable layer is stifferthan the other two layers. An example of such a manipulation is shown inFIG. 5.

Referring to FIG. 5, an adjustable pressure-relief shunt 400 similar tothat which is described above is shown. The pressure-relief shunt isbeing expanded by a balloon catheter 501. The balloon catheter extendsfrom the inferior vena cava 103 into the right atrium 105 and throughthe shunt. A guide wire 503 extends from the balloon catheter and may beused to initially cross the shunt and then provide a rail for thedilation catheter placement. The balloon catheter may be inflated with aradio-opaque die in order to allow for precise control of the deformeddiameter of the interatrial shunt. The dilation balloon may be acarefully sized non-complaint balloon. Alternatively, the dilationballoon may be a complaint balloon and the inflation pressure may becarefully controlled in order to achieve the desired shunt diameter. Insome embodiments the adjustable inventive device is configured with aninitial diameter around 3 to 4 mm and may be safely expanded up to 10mm.

In embodiments the adjustment of the inventive device of FIG. 5 mightbegin with an echocardiography analysis of the blood flow through theshunt and an analysis of the patient's diastolic pressure, total cardiacoutput, pulmonary arterial pressure, and pulmonary venous pressures. Ifit is determined that the shunt should be adjusted the user might thencarefully select the appropriately sized balloon. After gaining accessto the vascular anatomy by conventional techniques a user may advance aguide wire into the right atrium and carefully direct the wire throughthe inventive device. The guide wire may then be used as a rail and theselected balloon may then be positioned inside the interatrial shunt.The balloon would then be carefully inflated until the desired diameteris achieved. The balloon is then deflated and withdrawn. The user maythen repeat the analysis steps and further adjust the diameter of theshunt with additional balloon dilations if desired. In some embodimentsof the present invention the initial diameter of the inventive device isconfigured to be very small such that the initial amount of blood flowthrough the valve is unlikely to cause rebound stress or shock. The userwould then increase the diameter of the shunt as part of a routinefollow-on procedure or as a delayed part of the initial implantationprocedure.

The deformable and adjustable inventive devices of FIGS. 4 and 5 may beconfigured to be elastically adjusted by means other than a ballooncatheter. For example, a inventive device may be designed such that theinternal diameter of the shunt is adjusted by an axial compression orexpansion. In other embodiments the shunt may be adjusted by a windingor unwinding action, or by a puckering, folding, or unfolding action.

Turning now to FIG. 6, a further embodiment of the present invention isdepicted which may be adjusted in vivo from providing a first flow rateacross a membrane of the patient's heart, e.g., the atrial septum, tohaving a second flow rate. The second flow rate may be selected as theresult of evaluating the patient's heart condition at a time after theimplantation of the device An interatrial shunt 201 is shown asimplanted into an atrial septum 107. The interatrial shunt is comprisedof a tubular body 203 and a series of fastening members 205. The tubularbody of FIG. 3 is formed by a tightly wound coil 601. The interfacebetween the coils at either end of the tubular body features a series ofone directional ramps 603. On the left atrial side of the tightly woundcoil is a left side adjustment tang 605 and on the right atrial side ofthe tightly would coil is a right side adjustment tang 607. Theadjustment tangs encroach into the internal diameter of the shunt inorder to allow for the user to engage the adjustment tangs with anappropriate adjustment catheter.

The tightly wound coil 601 of FIG. 6 may be made of any of the materialsmentioned above, including nitinol, stainless steel, or a polymericmaterial. The fastening members 205 may be connected to the coil at oneend of the device such that the majority of the coils are able to bemanipulated and repositioned relative to the tissue fastening members.Alternatively, the adjustment coil 601 may be configured to rotateindependently of the fastening members while simultaneously beingaxially constrained relative to the fastening members 205. Finally, thefastening members 205 may be connected to a separate tubular body whichlies within and is constrained by the tightly wound coil 601.

The tightly wound coil 601 of FIG. 6 together with the one directionalramp features and the adjustment tangs 605, 607 allow the user to adjustthe internal diameter of the shunt 201 by winding or unwinding the coil.For example, the user may use an appropriate adjustment catheter toengage the adjustment tangs 605, 607 of the interatrial shunt 201, andthen apply torque to the right adjustment tang 607 relative to the leftadjustment tang 605. The effect of this rotational adjustment would beto unwind the coil, 601 which in turn opens the internal diameter of theinteratrial shunt. The ramp features 603 allow for the unwinding motionof the coils, but lock this motion in place, preventing the coils toreturn to their normal state. If the user wishes to reverse thisoperation the ramps 603 may be circumvented by separating or stretchingthe coils axially, thereby over-riding the ramp features 603. The numberof turns of the coil 601 is carefully configured such that the coilrepresents enough length such that it is longer than septum's thicknessin order to shunt the blood from the left atrium to the right atrium.The number of coils is further configured such that a reasonable numberof rotations are required to effect a preselected diametrical change inthe shunt 201. For example, the number of coils and the initial diameterof the shunt may be configured such that one 360 degree unwinding of thecoils increases the diameter by 2 mm. The coil 601 may be configured tocreate an adjustable inventive device with an internal diameter rangingfrom roughly 4 mm to 10 mm.

The interatrial shunt 201 of FIG. 6 is configured to be implanted by anappropriate delivery catheter. The interatrial shunt is configured tocollapse into the catheter either by increasing the number of winds andthereby decreasing the diameter, or by unwinding the coil 601 andstraightening the wire. The exact configuration of the interatrial shuntin its collapsed configuration depends on the material and design of thecoil. For example, if the tightly wound coil is made of a super-elasticnitinol wire then the coil may be completely unwound and advancedthrough a catheter with a very small internal diameter. Thesuper-elastic properties of the nitinol coil would allow the user tothen advance the wire through the catheter, which would recover itsinitial coiled configuration upon exiting the catheter tip. For astainless steel coil it would be more appropriate to conFig. the coil tobe delivered in a first collapsed diameter. The user would then deliverthe interatrial shunt by implanting it into the tissue and thendeforming the stainless steel coil with an unwinding motion until theimplant reaches a larger second diameter.

The adjustment tangs 605, 607 of FIG. 6 are configured to be engaged ordisengaged in vivo in a repeatable manner by an adjustment catheter. Theadjustment catheter includes an inner and an outer shaft, each of whichis configured to transmit torque relative to the other. For example, theadjustment catheter may include a braided outer catheter shaft and atri-filar inner catheter torque transmitting shaft. Alternatively theadjustment catheter may include a laser cut hypotube which is designedto transmit torque. The engagement of the catheter with the adjustmenttangs may be assisted by the use of radio-opaque markers incorporatedwithin the shunt near the adjustment tangs. The adjustment catheterinner and outer shaft may each feature a slot for engaging with theadjustment tangs. The slots include a generous lead-in in order to helpposition the catheter. The slots may be tapered to lock the tangs intothe adjustment catheter. The adjustment catheter may include anexpandable basket or expandable support wires in order to center thecatheter within the interatrial shunt. Alternatively the adjustmentcatheter may incorporate a snaring mechanism to ensnare the adjustmenttangs. The inner and outer adjustment catheter shafts may then interactwith the snaring features in order to engage the adjustment tangs.Finally, a series of adjustment tangs may be used to create a shape thatcan be keyed off of by a catheter. For example, the left side of thecoil may feature three adjustment tangs which create a clover shapedinternal profile in the inventive device. This profile may then beeasily engaged by an appropriately shaped adjustment catheter.

In use a physician would advance the adjustment catheter into theinternal diameter of the interatrial shunt. The adjustment catheter maybe tracked over a wire which has been placed through the shunt and intothe left atrium. The left side and right side adjustment tangs 605, 607would then be engaged by the adjustment catheter using any of the abovedescribed engagement methods, including simply keying the tangs into apair of slots. The left side adjustment tang 605 would be keyed into theinner shaft of the adjustment catheter while the right side adjustmenttang 607 would be keyed into the outer shaft of the adjustment catheter.The left side adjustment tang 605 may be held stationary by the inneradjustment catheter shaft, while the outer adjustment catheter shaftwould then be rotated by the user in the appropriate direction to unwindthe coil 601 and increase the inner diameter of the shunt.Alternatively, the right side adjustment tang 607 may be held stationaryby the outer adjustment catheter shaft while the left side adjustmenttang 605 is rotated by the inner adjustment catheter shaft. In eithercase, the fastening features of the inventive device would be connectedto the side of the shunt that is held stationary relative to the body.In this way the shunt is not simply rotated within the interatrialseptum. In some embodiments the user may be able to reset the coil backto its initial configuration by axially stretching the tightly woundcoil and thereby disengaging the one-directional ramps 603 and allowingthe coil to wind or unwind as needed.

The adjustable interatrial inventive device of FIG. 6 may be modified toallow for reducing the internal diameter of the inventive device withthe adjustment catheter. This may be accomplished by simply reversingthe directions of the one-direction ramps 603, such that a windingmotion instead of an unwinding motion may be locked in by theone-directional ramps. In this case the shunt may be deployed in acollapsed delivery diameter and then expanded to a first implanteddiameter by the user. The user may then decrease the size of theinteratrial shunt by winding the coil 601 in a similar manner to thatdescribed above. Once again, the user may be able to reset theinteratrial shunt to the initial deployed diameter by axially stretchingthe coils to over-ride the one-directional ramps.

Turning now to FIGS. 7-8B, alternative interatrial shunts are depicted.The inventive devices illustrated in these drawings are the same as eachother except as noted below. The interatrial shunt of FIG. 7 includes astent-like elongate tubular body 701 and a series of anchoring members205. The stent-like frame of the tubular body includes a series ofdiamond shaped struts 703. Each diamond shaped strut features a pairlaser cut eye-holes 705. The diamond shaped struts and eye-holes arespaced around the circumference and the length of the stent-like frame.Bio-resorbable suture material 707 is shown tied between various pairsof eye-holes. The suture materials are tied such that the stent is heldin an elongated state by the presence of the suture, as the diamondshaped struts are held stretched out axially. The stent frame istherefore shown in an elongated state in FIG. 7. The suture material isdesigned to be slowly absorbed by the body over time, which in turnallows the diamonds struts to return to their relaxed configuration. Therelaxed diamond struts in turn exert a radially outward force, causingthe stent member to expand radially as the suture material is absorbedinto the body. In this way the inventive device of FIG. 7 represents ameans for automatically and gradually changing the amount of blood flowthrough a inventive device in order to provide a non-static treatmentfor diastolic dysfunction.

The stent-like frame of may be made from a laser cut nitinol hypotube ina manner that is very similar to the manufacture of many stents. Thelaser cut nitinol hypotube may then be heat set to a predetermined finaldiameter. The heat set stent frame may then be stretch axially and thenthe suture knots tied around the eye-holes of the stent frame. The stentframe features sets off axially stiff members 709 (identified in FIG.8A) between the various diamond-shaped struts. The axially stiff membersare configured to help maintain the integrity of the stent frame suchthat the force required to stretch the diamond struts axially does notsimply collapse the stent frame between the struts. The initial diameterof the stent frame may be configured such that the inventive deviceallows only a small amount of blood to flow through the shunt.Furthermore, the number, size, and shape of the diamond struts may becarefully selected such that the final diameter of the shunt after theloss of the suture loops reaches a size that allows sufficient bloodflow through the shunt to treat the majority of the patient population.Still further, the amount that the diamond shaped struts are stretchedmay be configured such that a predetermined amount of mechanicaladvantage is built into the expanding action of the stent frame.

The bio-resorbable sutures of the devices of FIGS. 7-8B may be made fromany number of known absorbable suture fibers, including polyglycolicacid, polylactic acid, polydioxanone, or polycaprolactone. Themanufacture of bio-resorbable sutures is well known in the art.Absorbable sutures of various sizes may be used to delay or stagger theeffect of the expanding action of the inventive device. Bio-absorablesutures may have a diameter ranging from 0.1 mm to 0.7 mm (USP sizes 6-0to #3 respectively). In addition, the bio-resorbable sutures may be amonofilament construction, or may be braided. The bio-resorbablesubstrate may instead include a suture-like structure of anycross-sectional geometry, including a film-like structure, a thintape-like structure, or a rectangular or triangular cross-section. As anexample, initially a rapid expansion may be desired and so very thinsutures are used at strategic locations to allow for the initialexpansion of the shunt. Subsequently, a much slower expansion may bedesired, and this secondary expansion phase may be accomplished by usinga much thicker suture material on a second set of expansion struts. Theinventive device may be configured to expand gradually from roughly 4 mmto roughly 10 mm over the course of a number of days, weeks, or months.

FIG. 8A shows a more detailed view of the inventive device describedwith regard to FIG. 7. The action of the eye-holes 705 and the diamondshaped struts 703 can be more clearly seen in FIG. 8A, although themechanisms are the same as described above. The inventive device of FIG.8A is shown with a lesser expansion ratio than that of FIG. 7, as thediamond struts are stretched less such that when the sutures areabsorbed into the body the shunt will expand less. This may be desirablefor patients with toughened septal tissue, as the lesser expansionallows for the use of stiffer diamond struts which are capable ofexerting a larger outward radial force. The bio-resorbable suturematerial may be made from any of the above mentioned materials and mayinclude any of the above mentioned configurations. In addition, thebio-resorbable sutures may be replaced by any other suitablebio-resorbable substrate, including a sheet of bio-resorbable material,a bio-resorbable mesh, or a bio-resorbable film.

Upon sufficient dissolution of the bio-resorbable restraints, the deviceshown in FIGS. 7 and 8A will bulge radially outward to assume a barrelshape thereby increasing the hydraulic diameter of the device so as toincrease the flow rate therethrough. A variation of the device of FIGS.7 and 8A is shown in FIG. 8B. The device of FIG. 8B is similar in allrespects to that of FIGS. 7 and 8A except that it contains expandablesections 711 along its axial stiff members 709. Upon sufficientdissolution of the bio-resorbable restraints, the expandable section 711cause an increase in the longitudinal length of the body 701 and acorresponding contraction of its diameter, thus decreasing its hydraulicdiameter and the flow rate therethrough.

Turning now to FIG. 9, a inventive device 901 is shown as viewed fromthe central axis of the shunt. The inventive device consists of atubular body 203 and a series of anchoring members 205 which extendradially outward from the shunt body. The anchoring members again areused to anchor the inventive device to the septum. The tubular body ismade of a stent-like frame. An optional internal liner (not shown) maybe used to ensure that blood flows through the shunt from the leftatrium and into the right atrium instead of through the side wall of thetubular body. The tubular body of the shunt is periodically broken intoby a series of inward folds 903 of the tubular body. The inward foldsare held in place by bio-resorbable sutures 707 similar to those used inprevious embodiments. The inward folds are configured to take up spaceinside the shunt, and thereby limit the amount of blood flow through theshunt. As the sutures are absorbed into the body the folds areconfigured to gradually straighten out, and the inventive device isthereby expanded. The expansion by loss of the inward folding is causedboth by the direct expansion of the inventive device as well as by thefact that the folds impede blood flow and as they disappear the blood isable to flow through the shunt more efficiently.

Referring now to FIGS. 10A-10D an embodiment of the interatrialinventive device is depicted as it gradually transforms over time. Theinteratrial shunt of FIGS. 10A through 10D is designed to be implantedwith a first effective internal diameter. The shunt is then configuredto gradually expand over time to a second, substantially largereffective internal diameter. Finally, after a longer but stillpredetermined amount of time the inventive device of FIGS. 10A-10D isconfigured to contract to a third effective internal diameter which issubstantially smaller than the second effective internal diameter. It isto be noted that the intra-atrial shunt of the presently invention maybe configured to adjust to an multitude of progressively larger orsmaller diameters, and thus is not limited to the three progressivelylarger diameters described in connection with FIGS. 10A-D.

FIGS. 10A-D depict another embodiment of inventive device. FIG. 10Ashows an exploded side view of interatrial inventive device 1001. Thestent-like frame 1003 is shown about to receive the internal sheath 1005to which it will be subsequently attached. For clarity sake, only asmall portion of the frame 1003 is shown in FIGS. 10B-10C.

Referring now to FIG. 10B, an interatrial inventive device 1001 isdepicted. The inventive device includes an elongate tubular body 203 anda series of anchoring members 205. The elongate tubular body includes astent-like frame 1003 and an internal sheath 1005. The stent-like frameis once again constructed from a super-elastic material, such asnitinol. The stent-like frame includes a left end 1007 and a right end1009, the left end points into the left atrium 109 and the right endprotrudes into the right atrium 105. The left end is designed with aconical opening 1011. The conical opening is manufactured by creating awedge shaped cut out of the tubular frame and folding the frame suchthat the cut edges are adjacent to each other. The left end of the frameis cut such that the opening is fully open in the relaxed configuration,but has been compressed and sewed as pictured with bio-resorbablesutures 707. The bio-resorbable sutures of the left end are configuredto be absorbed by the body over a predetermined period of time. Forexample, in some embodiments the sutures are designed to be absorbed in10 to 30 days time. As the sutures dissolve into the body the left endopening is configured to gradually expand, such that the amount of bloodflow through the device gradually increases. As the last suture isabsorbed into the body the interatrial shunt reaches its maximumdiameter. The maximum diameter of the interatrial shunt is carefullyconfigured in order to allow for a therapeutic amount of blood to flowthrough the device. In some embodiments this maximum diameter may bebetween 6 mm and 10 mm.

Referring now to FIG. 10C, where the interatrial inventive device ofFIG. 10B still with a left end 1007 and a right end 1009 is depicted asimplanted into the atrial septum 107. The left end bio-resorbablesutures have dispersed into the body and the internal diameter hasreached its peak size. The inventive device is configured to remain atthis configuration for a predetermined amount of time. The duration ofthe shunt remaining at its maximum effective internal diameter iscontrolled by the right end bio-resorbable substrate. The right end iscut or shape set in a normally closed configuration. The shunt is thenexpanded and the expansion is locked in place by the bio-resorbablesubstrate. As shown in FIG. 10C, the bio-resorbable substrate may be aseries of bio-resorbable sutures 1013. The sutures are able to hold theright end of the interatrial shunt open due to the structure of theright end stent-like frame, which features a series of diamond shapedstruts 1015, similar to those depicted in FIG. 7. The diamond shapedstruts are designed such that the major axis of the diamond points alongthe axis of the device and is much longer than the minor axis of thediamond. On either end of the major axis of the diamond shaped strutsare eye-holes 705, through which sutures may be tied. A suture is tiedbetween the two eye holes on the diamond shaped struts and the majoraxis of the diamond is compressed. This in turn causes the minor axis toexpand, with the net result being the expansion of the circumference ofthe shunt which finally leads to the expansion of the overall diameterof the shunt. The amount of expansion may be controlled by the length ofthe suture knot, the shape of the struts, or the number of diamondstruts that wrap around the circumference of the inventive device. Theright sided bio-resorbable sutures are configured to take a much longertime to absorb into the body than the left side sutures. For example,the right side sutures may be made of a USP size #1 suture while theleft side bio-resorbable suture may be a USP size 4-0 suture or smaller.

Turning now to FIG. 10D, the interatrial inventive device of FIG. 10Band 10C is depicted in its final configuration, where the left side 1007has opened up fully, and much later the right side 1009 has closedfully. The diamond shaped struts 1015 are shown in the relaxedconfiguration and the right side is overall at its lowest energy state.The size of the final right side orifice may be configured such that aminimum amount of blood is allowed to flow through the device such thatsome therapeutic treatment may be expected of the shunt without the riskof the adverse events of associated with significant long term left toright shunting of blood. In this way FIGS. 10A-D represent a means fortreating diastolic heart failure dynamically.

Turning now to FIG. 11, a method for treating diastolic heart failure isoutlined. The method includes first analyzing or characterizing thepatient's diastolic dysfunction through means that are well described inthe art, including trans-esophageal echocardiography, trans-thoracicechocardiography, MRI, CT, or catheterization. The method furtherincludes using the data gained from the analysis to select a inventivedevice to be implanted into the interatrial septum with a preselectedinternal diameter. The inventive device may be any of the adjustableinventive devices described herein or any of their equivalents. Theinventive device is configured to allow an amount of blood flow throughthe shunt that is determined by the analysis to be unlikely to cause anyshort term shock or pressure spikes for the patient. The method thenincludes a waiting period where the patient's heart is given time togradually adjust to the newly improved hemodynamic conditions. Next asecond series of analysis is then carried out, using similarmethodologies to those described above. The second analysis is used todetermine whether additional adjustment of the shunt would be beneficialfor the patient. If the adjustment is thought to be beneficial based onthe analysis then the method includes using an appropriate adjustmentcatheter or adjustment balloon catheter to adjust the inventive deviceand thereby change the amount of blood flow through the shunt in orderto benefit the patient. The adjustment may include increasing theinternal diameter of the inventive device in order to allow additionalblood flow through the device or it may instead include decreasing thediameter of the shunt in order to prevent complications such as thedevelopment of hypertrophic pulmonary arteries. In this way the methodoutlined in FIG. 11 represents a method for treating diastolic heartfailure in a dynamic and adjustable manner.

While the foregoing description focused on embodiments thatautomatically adjust the flow rate through the shunt, the presentinvention also includes embodiments which the flow rate adjustment ismade manually or a combination of manually and automatically. Someembodiments which may include automatic, manual, or a combination ofautomatic and manual rate adjustments are described below.

This disclosure concerns an adjustable shunt for allowing flow from anarea of high pressure, such as a left atrium of a heart, to an area oflower pressure, such as a right atrium of a heart. As explained above,this device may help to relieve over-pressure and may aid in preventinghypertrophy in the affected blood vessels. FIG. 12 discloses across-section of a multi-part intra-atrial shunt 11 placed into a septumand held in place by the septal wall of a person's heart. The shunt 11includes two parts, a retaining cage 15 directly attached to the septalwall, and an insert 17 attached to the cage 15 and retained in place bythe cage. In this embodiment, the shunt 11 may be relativelysymmetrical, i.e., the portion of the shunt retained in the left atriumis substantially similar to the portion of the shunt retained in theright atrium. In addition, the tubular central portion may be relativelyuniform along its length.

A closer and more detailed view of a shunt embodiment is disclosed inFIG. 13. In this embodiment, the shunt 11 includes cage 15 and insert17, the cage and the insert also including retaining features that allowthe insert to reversibly lock into the retaining cage. Cage 15 includesa right atrium flange 15 a which is substantially similar to left atriumflange 15 c. The intermediate portion 15 b is substantially tubular,with a retention feature 15 d, which may be a void or a space, i.e., anindentation or some other receptacle, available on the outer surface ofthe cage. Cage 15 may be made of struts and apices of nitinol, thenitinol having a martensite/austenite transition below 37° C.,preferably in the neighbourhood of about 25° C., so that the cageremains in its superelastic, austenitic phase during use inside a bodyof a human or a mammal.

The other portion of the adjustable shunt is the insert 17, which may beimpermeable and may allow flow of blood or other fluid only through itscentral passage. Insert 17 includes an outlet 17 a and an inlet 17 cthat is substantially similar to the outlet. The central portion 17 b isgenerally tubular and not permeable to fluids, with an outer surfacehaving a retention feature 17 d for matching with the retention feature15 d of cage 15. Insert 17 may be formed from a polymer such as PTFE,UHMWPE, HDPE, polypropylene, polysulfone, or other biocompatibleplastic.

Retention feature 17 d may be a tab or a button for placing into a voidor space of cage 15. It will be understood by those having skill in theart that the inner diameter or dimension of insert 17 determines bloodflow from the higher pressure left atrium to the lower pressure rightatrium of the patient into whom the shunt is implanted. It will also beunderstood that the cage 15 will be implanted first with the insert 17later implanted into the cage. Both the cage and the insert have aremoval feature 15 e, 17 e, such as a loop of suture or of a radiopaquematerial included into the retrieval loop. Examples of radiopaquematerials may include a gold or platinum thread. A retrieval device,such as a snare or grasper, may be used to grasp the retrieval loop forremoval from the patient or re-placement within the patient.

The retention feature is important because the insert will only controlthe flow of blood from an area of higher pressure to an area of lowerpressure in the heart if it is retained in place. The retention featureis also important because it is this feature that allows the purposefulor intentional removal of the insert, so that the insert can be replacedwith an insert of a lesser or greater diameter, depending on whether alesser or greater amount of pressure relief is required for the patient.As noted above, the amount of relief, that is, the radius or hydraulicradius of the opening, may vary among patients and may vary in time fora given patient. Thus, a multi-part shunt, with inserts of differenteffective hydraulic diameters, may be used to allow relief to a patient.To be clear, it is to be understood that a multi-part shunt may includea plurality of inserts and one insert may be replaced by another in vivoas need be to achieve the desired flow rate for the patient. It isclearly a less traumatic surgical procedure to replace the insertdescribed here than to implant the entire shunt, and in particular, toimplant the cage. Once the cage has been implanted, subsequentprocedures are accomplished more quickly and with less trouble to thepatient. The inserts, for example, may have inner diameters from 0 to 15mm, including inserts having inner diameters from 3 to 5 mm. This is thediameter of the flow path from a higher pressure area to a lowerpressure area.

Another embodiment is depicted in FIG. 14. In this embodiment,adjustable intra-atrial shunt 21 includes a cage 25 with a positive orprotruding retention feature 25 d, such as protruding tab or ridge onits inner side. Insert 27 includes a groove 27 d to receive theprotruding rib or ridge from the cage 25. Thus, the insert is retainedwithin the cage.

In another embodiment depicted in FIG. 15, insert 31 includes an innerportion of reduced diameter 33, the portion with reduced inner diametermolded to that shape or produced by one or more secondary operations.Using this technique, a single insert shell or form may be used and thenadapted or adjusted to the desired shape. For example, an inner formwith the reduced diameter may be bonded to the inside of a standardshell by solvent bonding, ultrasonic welding, or other technique. Thisallows producers to have one or more basic insert shapes that may thenbe individualized using a series of forms, or third parts. In oneembodiment, the inner diameter is reduced to zero, so that an attendingphysician or medical professional may entirely close the shunt,preventing blood flow altogether between the left and right atria.

It is desirable that the inserts and cages be retrievable, as notedabove with respect to the retrieval loops shown in FIG. 13 for both thecage and the insert. A variety of other features besides loops may beused to retrieve the components of the adjustable intra-atrial shunt.Thus, insert 35 is depicted with a snare leg 37 in FIG. 16 and with a“wind sock” or lengthened end 39 in FIG. 17. These features may also beadded to the cage portions of the intra-atrial shunt for easy retrievalof the cage, and subsequent removal or re-positioning within thepatient.

The above embodiments are useful for adjusting the diameter of theshunt, but while useful, each adjustment is fixed. Other embodiments areconstructed so that the openings or orifices gradually increase ordecrease over time. In the embodiment of FIG. 18, flow control elementor insert 90 has an outward form of a thin cylinder. Insert 90 includesa frame, which may include an outer circumference, and a plurality offlaps 91. The flaps are made of a polymer such as PTFE, UHMWPE, HDPE,polypropylene, polysulfone, or other biocompatible plastic. Otherembodiments may use extracellular materials or other suitable biologicmaterials. The flaps are sewn together with biosorbable sutures, such aspolylactic acid, polyglycolic acid and polycaprolactone, other suitablebiosorbable sutures, or combinations of these. There may also be aninitial orifice 93 in the center so that flow will occur upon placementof the insert 90 into a cage. The sutures provide tension between theflaps and keep the flaps closed. As the sutures absorb, the tension islost and the flaps open. Other embodiments may include no initialorifice.

When insert 90 is first deployed, orifice 93 allows limited flow. Overtime, material from the sutures will be absorbed gradually into thebloodstream. The sutures will become thinner and weaker, and the jointbetween any two of the flaps will become looser, allowing more bloodflow. Some of the suture joints may use more sutures and some may useless, so that the weakening of the sutures increases gradually overtime, rather than all at once. Accordingly, insert 90 will have aninitially low flow of blood from an area of high pressure to lowpressure, due to a small initial orifice. Later, as the sutures arebiosorbed and the flap joints become looser, blood flow will increase.If more adjustment is needed, the insert 90 may be removed via retrievalloop 99 and replaced with another insert, such as one depicted in FIGS.13-15 of the present application. Retrieval loop 99 is desirably notbiosorbable and may include a radiopaque member as discussed above.

The insert portion of another embodiment which utilizes an insert/cagecombination is depicted in FIG. 19A. The insert portion of the inventivedevice of FIG. 19A is also shown in a cross-sectional view taken alongline 19B-19B. In this embodiment, insert 95 may be a plate may ofbiocompatible plastic, with a plurality of orifices 96 and flaps 97above the orifices, the flaps sewn in place as shown with biosorbablesutures. One or more of the orifices may have no flap, the orificeintended to provide an initial opening that remains constantly openwhile the insert 95 is deployed with a cage as shown above. When theinsert is first deployed, the one or more orifices without flaps willprovide flow. Over time, the sutures will be absorbed and will no longerbe able to prevent the flaps 97 from covering the orifices, thusdecreasing the openings and the flow from the area of high pressure tothe area of low pressure. In some cases, the sutures provide tension toretain the flaps in place, keeping the flaps in place and the flapsopen; as the sutures absorb, the flaps deploy to close the orifices.Insert 95 may be retrieved and removed via retrieval loop 99.

In some embodiments, the insert may be easier to fabricate if the flowcontrol portions are placed near an end, i.e., an outside of the insert,as shown in FIGS. 20 and 21. For example, FIG. 20 depicts a tubular flowcontrol element 90 a, in the form of a hollow tube intended forplacement within one of the retainers discussed above. In this example,a flow control element 91 a is fabricated from a biosorbable polymerfilm, using biosorbable materials discussed above. The flow controlelement 91 a may be fabricated with an initial orifice 93 a, such as acentral orifice, or it may be fabricated as a solid film, with no flowpermitted through the device. Control of the absorption and loss of massfrom the film may be easier to control with even a very small centralorifice. After the flow control element in implanted into a patient, thefilm absorbs into the patient and becomes thinner and thinner, while thecentral orifice becomes larger and larger, allowing more blood flow asthe orifice enlarges. In one embodiment, the thickness of the film maybe graduated, with the thinnest portions at the center, with gradualthickening as the film approaches its circumference. The film may bebonded to the structure by ultrasonic bonding or other reliable methodthat prevents loosening or disassembly of the film from the structureduring implantation. With this device, initial flow is low, but as thefilm absorbs into the patient, more and more flow is allowed as theorifice 93 a grows.

Although the descriptions given above for the embodiments having insertsthat the inserts were described as being removable, it is to beunderstood that the present invention also includes embodiments whereinthe inserts are not removable. In some such embodiments, the inserts arepermanently attached to the cage, and in still other embodiments whatare described above as inserts are not inserts at all but are integralportions of the cage. It is also to be understood that in someembodiments, the first anchor, the second anchor, and the shunt areintegrally connected.

In another embodiment, depicted in FIG. 21, a hollow flow controlcylinder 95 a includes one end with one or more orifices 96 a. In thisembodiment, one or more orifices, such as each orifice, is open and isnear a flap 97 a that is secured to the cylinder on one end. The otherend of each flap is tethered to the cylinder with one or morebiosorbable sutures 98 a. Upon implantation, all the orifices will beopen and will allow flow of blood. As the suture or sutures biosorb, thetop end of each flap, as shown in FIG. 21, will become loose and maydrop down to block the orifice 96 a closest to that flap. Eventually,all the flaps will become loose and each flap will block the orificeclosest to it, blocking flow of blood. However, the device of FIG. 21may have one or more additional orifices without a flap, so that thereis some blood flow even after all the sutures have absorbed. With thisdevice, initial flow is relatively high, but as the sutures absorb intothe patient, more and more of the orifices are blocked, cutting downflow, and if all orifices are blocked, flow is effectively stopped.

While the invention has been disclosed in connection with the preferredembodiments shown and described in detail, various modifications andimprovements thereon will become readily apparent to those skilled inthe art. Accordingly, the spirit and scope of the present invention isnot to be limited by the foregoing examples, but is to be understood inthe broadest sense allowable by law.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) is to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

While embodiments have been disclosed and described in detail, it isunderstood that various modifications and improvements thereon willbecome readily apparent to those skilled in the art. Accordingly, thespirit and scope of the present invention is not limited by theforegoing examples, but is better understood by the claims below. Allpatents, published applications, and other documents identified hereinare incorporated by reference herein in their entireties to the fullextent permitted by law.

What is claimed is:
 1. A device adapted for percutaneous delivery into amembrane of a patient's heart, the device comprising anchors which areadapted to hold the device in place within the aperture by contactingfirst and second sides of the membrane of the patient's heart, and ashunting section connected to the anchors, the shunting section having afirst diameter at a first time after delivery and a second diameter at asecond time after delivery, and the first time different from the secondtime, wherein the shunting section has a first length corresponding tothe first diameter and a second length corresponding to the seconddiameter, the first length greater than the second length.
 2. The deviceof claim 1, wherein the first diameter is less than the second diameter.3. The device of claim 1, wherein the second diameter is less than thefirst diameter.
 4. The device of claim 1, wherein at least a portion ofthe shunting section is biased to cause the shunting section to have afirst hydraulic diameter.
 5. The device of claim 4, wherein the shuntingsection is adapted to have a second hydraulic diameter upon removal ofat least portion of the bias.
 6. The device of claim 1, wherein at leastone of the shunting section and the pair of anchors comprises a shapememory material.
 7. The device of claim 1, wherein the shunting sectionis adapted to change from the first diameter to the second diameterautomatically.
 8. The device of claim 1, wherein the shunting sectionhas a third diameter.
 9. The device of claim 8, wherein the thirddiameter is greater than at least one of the first and second diameters.10. The device of claim 8, wherein the third diameter is less than atleast one of the first and second diameters.
 11. The device of claim 8,wherein the shunting section is adapted to change from the seconddiameter to the third diameter automatically.
 12. An expandable deviceadapted for percutaneous delivery into a membrane of a patient's heart,the device comprising: first and second anchors adapted to contact,respectively, a first side and a second side of the membrane of thepatient's heart; and a shunt connected to the first and second anchorsand having a bio-resorbable material, the shunt comprising a first innerdiameter, changing to a second, different inner diameter, the seconddiameter greater than the first diameter; upon absorption of at least aportion of the bio-resorbable material.
 13. The device of claim 12,wherein at least a portion of the shunting section is biased by thebio-resorbable material to cause the shunting section to have a firsthydraulic diameter.
 14. The device of claim 12, wherein the shunt isfurther adapted to permit blood to flow across the membrane at a thirdflow rate upon further absorption of at least a portion of thebio-resorbable material.
 15. The device of claim 14, wherein the thirdflow rate is greater than at least one of the first and second flowrates.
 16. The device of claim 14, wherein the third flow rate is lessthan at least one of the first and second flow rates.
 17. The device ofclaim 12, further comprising a protruding member adapted to be engagedby a percutaneous retrieval device.
 18. The device of claim 12, whereineach of the first and second anchors comprises a plurality of segments.19. The device of claim 12, wherein the first anchor, the second anchor,and the shunt are integrally connected.
 20. The device of claim 12,wherein the absorption of the bio-resorbable material occurs at apre-determined rate.
 21. An expandable device adapted for percutaneousdelivery into a membrane of a patient's heart, the device comprising:first and second anchors adapted to contact, respectively, a first sideand a second side of the membrane; and a shunt having a first dimensionand connected to the first and second anchors, the shunt being adaptedto permit blood to flow across the membrane at a first flow ratecorresponding to a first dimension and comprising a frame having aplurality of struts, wherein at least a set of the struts areinterconnected by a first bio-resorbable material configured to degradewhile the struts remain, wherein the shunt has a first dimension whenthe first bio-resorbable material is intact and a second dimension whenthe first bio-resorbable material is not intact, and wherein the shuntis adapted to permit blood to flow across the membrane at a second flowrate corresponding to the second dimension.
 22. The device of claim 21,wherein each of the first and second anchors comprises a plurality ofsegments.
 23. The device of claim 21, wherein the first anchor, thesecond anchor, and the shunt are integrally connected.
 24. The device ofclaim 21, wherein the absorption of the first bio-resorbable materialoccurs at a pre-determined rate.
 25. The device of claim 21, furthercomprising a sheath situated within and attached to the frame.
 26. Thedevice of claim 21, wherein at least some of the struts are arranged indiamond-pattern sets, each of the diamond-pattern sets having a firstand a second diagonal.
 27. The device of claim 26, wherein at least someof the struts in the diamond-pattern sets are interconnected by thefirst bio-resorbable material to restrain the diamond-pattern sets towhich the interconnected struts belong from changing the length of theirrespective first diagonals.
 28. The device of claim 27, wherein theshunt has a longitudinal axis and at least some of the first diagonalsare aligned parallel to the shunt's longitudinal axis.
 29. The device ofclaim 27, further comprising a sheath situated within and attached tothe frame.
 30. The device of claim 21, wherein the shunt has a first endand a second end and at least one of the first and second ends isadapted to have a contracted configuration and a expanded configurationand the first bio-resorbable material interconnection is adapted toreleasably maintain at least one of the first and second ends in atleast one of its respective contracted and expanded configurations. 31.The device of claim 30, wherein the shunt further comprises a sheathsituated within and attached to the frame.
 32. The device of claim 21,wherein the shunt has a first end having a first contractedconfiguration and a first expanded configuration and a second end have asecond contracted configuration and a second expanded configuration, thefirst end being constrained by the first bio-resorbable material toreleasably maintain either its first expanded configuration or its firstcontracted configuration, and wherein the shunt has a second end havinga second contracted configuration and a second expanded configuration,the second end being constrained by a second bio-resorbable material toreleasably maintain either its second expanded configuration or itssecond contracted configuration, wherein the absorption of the firstbio-esorbable material occurs at a first pre-determined rate and theabsorption of the second bio-resorbable material occurs at a secondpre-determined rate that is different than the first pre-determinedrate.
 33. The device of claim 32, wherein the shunt further comprises asheath situated within and attached to the frame.
 34. An expandabledevice adapted for percutaneous delivery into a membrane of a patient'sheart, the device comprising: first and second anchors adapted tocontact, respectively, a first side and a second side of the membrane; acore segment interconnecting the first and second anchors and comprisinga bio-resorbable material, the core segment comprising a first diameterwhen the bio-resorbable material is intact, and a second, differentdiameter upon degradation of the bio-resorbable material, the seconddiameter greater than the first diameter.
 35. The device of claim 34,wherein the shunt and the core segment are integrally connected.